A core component of the ALL-EMA method is the collection of biodiversity data via habitat mapping.
Determining Habitat Type
The recording of habitat types is of primary importance for the ‘monitoring’ target. This means that the declines and increases in individual habitat types as well as differences between regions can be statistically proven for the greatest possible number of habitat types.
The habitats are defined according to the existing ‘Habitats of Switzerland’ typology of Delarze et al. (2008), which has become established as the standard in national projects such as Biodiversity Monitoring Switzerland, as well as in the central databases of InfoFlora and InfoFauna. Delarze et al. (2008) distinguish 174 different habitat typologies at association/community level (e.g. low-input permanent meadow).
The ALL-EMA project distinguishes 86 habitat types associated with the open agricultural landscape. A botanic key for the reproducible determination of these habitat types was developed in cooperation with Hintermann & Weber AG and further external experts. The determination is conducted in accordance with the plot sizes for vegetation surveys in Biodiversity Monitoring Switzerland on standardised circular plots of 10m2. The key has been tested in single and double mappings by botany experts.
Quality of Habitats
The mere determination of habitat type allows initial conclusions to be drawn as to the range of species diversity on a particular site. Within the habitat types, however, substantial qualitative differences often exist at different sites.
To allow us to record and assess habitat quality, individual lists with 25 plant species each were developed in consultation with experts for a majority of the habitat types. These lists are used to rate quality in the field; with them, a complete vegetation survey is unnecessary.
The biological diversity of various species groups depends on the presence of specific structural elements in the landscape. In order to carry out the area-wide survey of woody structural elements, aerial images are analysed stereoscopically. For this, areas outside of the open agricultural landscape (forests, bodies of water, residential areas) are first masked out in the survey squares. After submission of the categories of land-use statistics, hedgerows and copses, individual trees and groups of trees, as well as individual clumps of shrubs and groups of shrubs are differentiated accordingly within the remaining open agricultural landscape.
The selection of structural elements to be recorded in the field is based on experience of national programmes such as the Inventory of Dry Grasslands and Pastures, land-use statistics, the Direct Payment Ordinance’s directives on low-impact pastures, and expert knowledge. Said structural elements are surveyed in the field on the same sample raster as the habitat types, on an area of approx. 200m2.
In addition to the structural surveys, surveys of the invasive neophytes are carried out within the same radius.